Geophysical Survey
Archaeologists are famous for large scale excavations, but there is much work to be done before the digging begins. The most important decision is where to dig. To find the best location, a geophysical survey is often conducted. The word geophysical (geo meaning “earth” and phys meaning “body” or “nature”) refers to the properties related to the geology of an area. These surveys are often used as a part of “off-site” archaeology, in which the entire landscape is investigated as opposed to just the structures. Off-site work is helpful when studying hunter-gatherers, who don’t always leave behind permanent structures.
The first step in a geophysical survey is a thorough walk through of the area. The archaeologist will take notes, make drawings and maps, as well as take pictures. This will make any above ground features more obvious. An archaeological feature is a permanent fixture of a site which is not a structure, such as a hearth, ditch, or post hole. Detecting features underground without digging is more difficult. Certain tools, such as the resistivity meter and the magnetometer, can be used to find such features. The resistivity meter measures the soil’s electrical resistance, and the magnetometer measures small changes in the Earth’s magnetic field. Archaeologists might also use a metal detector, but these can be faulty and often detect unimportant scraps of metal.
After an underground site is located, a probe or auger, sometimes with a small camera attached, might be lowered into the ground to obtain more information. Although it can damage artifacts beneath the surface, this technique is far less destructive than a full excavation. A geophysical survey is very useful to archaeologists, and often essential to the process of “unearthing the past.”
Archaeologists are famous for large scale excavations, but there is much work to be done before the digging begins. The most important decision is where to dig. To find the best location, a geophysical survey is often conducted. The word geophysical (geo meaning “earth” and phys meaning “body” or “nature”) refers to the properties related to the geology of an area. These surveys are often used as a part of “off-site” archaeology, in which the entire landscape is investigated as opposed to just the structures. Off-site work is helpful when studying hunter-gatherers, who don’t always leave behind permanent structures.
The first step in a geophysical survey is a thorough walk through of the area. The archaeologist will take notes, make drawings and maps, as well as take pictures. This will make any above ground features more obvious. An archaeological feature is a permanent fixture of a site which is not a structure, such as a hearth, ditch, or post hole. Detecting features underground without digging is more difficult. Certain tools, such as the resistivity meter and the magnetometer, can be used to find such features. The resistivity meter measures the soil’s electrical resistance, and the magnetometer measures small changes in the Earth’s magnetic field. Archaeologists might also use a metal detector, but these can be faulty and often detect unimportant scraps of metal.
After an underground site is located, a probe or auger, sometimes with a small camera attached, might be lowered into the ground to obtain more information. Although it can damage artifacts beneath the surface, this technique is far less destructive than a full excavation. A geophysical survey is very useful to archaeologists, and often essential to the process of “unearthing the past.”
Mary Mucci